Applying the ACRM Diagnostic Criteria for Mild Traumatic Brain Injury in Professional Rugby League Players

Research Objectives: The new American Congress of Rehabilitation Medicine (ACRM) diagnostic criteria for mild traumatic brain injury (mTBI) were published in 2023. We examined the feasibility and accuracy of applying the ACRM diagnostic criteria for MTBI retrospectively to ultra-acute assessment data from professional athletes who were medically diagnosed with concussions.

Design: This is a retrospective cross-sectional clinical study.

Setting: The National Rugby League, a professional sporting league in Australia.

Participants: Participants were 230 men who are professional rugby league players who were medically diagnosed as sustaining a concussion, by the team medical staff, during one of three consecutive sporting seasons (2017-2019).

Interventions: There were no interventions in this study.

Main Outcome Measures: The main outcome measures were clinical signs of concussion documented on administrative forms by the medical staff and the symptom reporting, cognitive functioning, and balance testing results derived from the sideline administration of the Sport Concussion Assessment Tool 5th Edition (SCAT5).

Results: Applying the ACRM diagnostic criteria for mTBI retrospectively, 85.7% met criteria for diagnosis and 7.4% met criteria for a suspected mTBI. There were 16 players (7.0%) who were diagnosed by medical staff as concussed but who did not meet ACRM criteria, mostly because there were no documented clinical signs, no documented clinical symptoms, and their scores on cognitive testing and balance testing were in the normal range. On the Maddock’s questions, relating to orientation and amnesia, approximately one in five missed a question (20.4%). During the sideline evaluation, 60.4% endorsed two or more of the ACRM clinical symptoms. The most endorsed ACRM symptoms, on the sideline, were headache (50.4%), dizziness (43.9%), and “don’t feel right” (40.9%). Their median score on the Standardized Assessment of Concussion (SAC) was 26 (IQR=23-28). Cognitive impairment, defined as a score of 23 or lower on the SAC, was present in 30.4%. Their median score on the modified Balance Error Scoring System (mBESS) was 5 (IQR=2-7). Balance impairment, defined as 7 or more error points on the mBESS, was present in 30.0%. Having cognitive impairment, balance impairment, or both was present in 50.4%.

Conclusions: This study illustrates that the new ACRM diagnostic criteria for MTBI, applied retrospectively to historically collected administrative and clinical data, identified more than 90% of professional rugby league players who were medically diagnosed with a concussion.

Author(s) Disclosures: Dr. Gardner and Dr. Iverson acknowledge unrestricted philanthropic support for research from the National Rugby League.